Capacitor Discharging Question

[CrazedBinary]

Hi everyone -

I own a B&K Precision HV44A High Voltage Probe Meter for CRT repair and was wondering if I could also use this to discharge power supply type capacitors (50-1000v). I didn't want to make a probe if I didn't need it.

Link to product:
http://www.bkprecision.com/products...ers/HV 44A-40kv-high-voltage-probe-meter.html

Thanks all -
CrazedBinary

 

[Electrobrains]

Sure you can!
You just need paatiiieeenceee...
The probe has 600MΩ internal resistance.

 

[CrazedBinary]

How long do you think it would take for say a 500 volt?

 

[Electrobrains]

Depends on the size of the capacitor.

Here is a good site where you can calculate the discharge (and charge) characteristics of capacitors:
http://mustcalculate.com/electronics/capacitorchargeanddischarge.php

Example:
In your case, with your probe (600MΩ), a 470μF capacitor charged to 500V, to reach 30V, it would theoretically take 220 hours (9 days!) and look like this:
http://mustcalculate.com/electronic...p?vfrom=500&vto=30&vs=0&c=0.00047&r=600000000

Of course it would take less time than that because the leakage current through the capacitor would discharge it in a fraction of that time.

 

[tedstruk]

I think I am going to cry... Electrobrain has posted a link to the most useful of all internet calculators... that is a great link... that is the best link on the internet...
I think I like link....
thanks EB.... I needed that!

 

[Electrobrains]

Yes, it's a very good site for many things!
http://mustcalculate.com/